Removal of slag from iron distributors used in the production of mineral wool



Jan. 24, 1956 M. DOWNEY 2,731,670

REMOVAL OF SLAG FROM IRON DISTRIBUTORS USED IN THE PRODUCTION OF MINERAL WOOL Filed NOV. 1, 1951 IN V EN TOR.

United States PatentO REMOVAL OF SLAG FROM IRON DISTRIBUTORS USED IN THE PRODUCTION OF MINERAL WOOL Richard M. Downey, North Judson, Ind., assignor to United States Gypsum Company, Chicago, Ill., a corporation of Illinois Application November 1, 1951, Serial No. 254,375

1 Claim. (Cl. 1847.2)

The present invention relates to the removal of deposits of slag from the iron or steel distributors used in the production of mineral wool.

In the production of mineral wool, slag wool, and the like, a stream of molten mineral material is allowed to impinge upon a rapidly rotating surface of a distributor from which it can be tangentiallly projected in the form of fine streams of molten material which are then intercepted by a strong blast of a gas, for example steam, not only to change the direction of travel of the said streams but also to attenuate them into fibers. These can then be collected by suitable means to form felts or bats, of mineral wool and the like.

In my co-pending application Serial No. 194,180, now Patent No. 2,646,593, I have disclosed a hollow rotor upon the interior side wall of which a stream of hot slag is allowed to fall, the rotation of the rotor causing the formation of a vertically positioned annulus of molten slag in contact with the wall. As this annulus moves to the rim of the rotor, streams of molten material are tangentially discharged from the periphery of the annulus. These streams are then intercepted by an annular blast of high pressure steam issuing from an annular nozzle, the steam blowing through the mass of the streams, thereby converting them into filaments or fibers, which are directed into a suitable collecting chamber. Any portions of the melted material which are too large to have their direction changed by the blast will continue on their outwardly directed tangential travel and hence will not get into the collecting chamber, with the result that the wool thus produced is much freer of shot and slugs than that heretofore made.

As described in my co-pending application Serial No. 254,373, now Patent No. 2,587,710, I resort to the expedient of internally cooling the rotor to a predetermined degree whereby the molten material in contact there with is conditioned to its point of optimum viscosity characteristics, so that fibers of the desired degree of fineness and length will be produced.

In the case of operations such as these just described, and both with cooled as well as with uncooled rotors, there exists a tendency for the molten material gradually to build up on the rotors, to form an adherent coating of what, for sake of simplicity, might be called a slag skull. It was given this name because, in a hollow rotor, it would form a sort of skull-shaped object. This skull or shell of slag could be removed without stopping the apparatus by reaching into the interior of the rotor with an iron hook or hoe, and pulling it out of contact with the iron surface. This was a rather delicate and dangerous operation, for if the skull adhered too strongly it might tear the hook or hoe out of the hands of the operator, and fling it about.

Accordingly it is one of the objects of the present invention to provide a process by which the adherent slag skull is practically self-removing, or where its removal is quick and certain and not attended by danger to the operator.

, for reducing the adhesion of the slag skull or shell to the interior of the rotor, so that its removal will be facilitated.

These objects are attained by the periodic application of a lubricant or the like to the rotor surface. It is not definitely known what takes place, that is, whether the lubricant acts as a parting compound or whether it is burned to form one; or whether the lubricant survives the heat of the molten slag and still functions as a lubricant. It is readily seen that it could hardly have been expected that a lubricant, which ordinarily serves to prevent too great friction between relatively moving surfaces, and brakes down about 750 F., would still function at temperatures within the range of from about 2500 F. to 3000 R, which is the temperature of the slag or other molten material which is to be formed into fibers.

The practice of the present invention comprises the periodic introduction of a relatively small amount of a lubricant into the system so that it will work its way to the interface between the slag and the metallic surface.

If sufficient lubricant is used, the mass or skull of slag will be automatically ejected from the rotor surface; and if not, a mere tap with a suitable tool will effect its ejection. In the normal operation of making mineral wool from a molten mass of material, such cleaning may be effected at intervals of from a few minutes up to about an hour, depending upon the nature of the molten material, the temperature at which it is blown into fibers, the surface condition of the rotor and other variables.

The placing of the lubricant or parting compound may be accomplished manually, or mechanical means may be provided to feed the lubricant to the desired point.

The lubricant or parting compound may consist of any of the well known mineral, vegetable, or animal oil lubricants, either in their pure state or in admixture with graphite, preferably in suspension in the oil or colloidally dispersed therein. Powdered graphite, without any oil, may also be used. Lubricating greases are also operative; in fact any organic material which will yield some form of carbon may be used.

In order further to disclose the invention and the manner of carrying it out, it is more or less diagrammatically shown in the concurrently filed drawings in which:

Fig. 1 is a side elevational view of a suitable rotor and the means for applying the lubricant; and

Fig. 2 is a cross-section thereof, along the line 2-2 of Fig. 1, with the melt spout and lubricant feed line extending outwardly before said line 2--2.

This apparatus, except for the means employed for the placing of the lubricant into the desired position, is substantially identical with that described in my copending applications Serial No. 194,180, filed November 4, 1950, and Serial No. 254,373 filed November 1, 1951, now Patent No. 2,587,710.

Referring now particularly to Figs. 1 and 2, it will be seen that there is provided a rotor 3 which may conveniently take the form of a hollow cylinder having an internal wall or surface 4, which may be parallel with the axis of rotation or may be inclined thereto so as to diverge outwardly. This rotor 3 is keyed or otherwise secured to a substantially horizontally disposed shaft 5.

Suitable bearings 6 and 7 serve to support the shaft, there also being provided a pulley 8, keyed to the shaft, over which runs a suitable driving means, such for example as the belt 9.

A suitable conducting chute 10 serves to direct a stream 11 of molten glass, slag or the like to a point so located that the stream 11 will be directed to the inner surface 4 charged from the periphery thereof under the centrifugal force as an annular mass of small closely adjacent streams 14 of melted slag.

Due to the rapid rotation of the rotor 3 and of course of the annulus 12 which partakes of this motion, the visual appearance of this mass of material is that of an annular relatively thin ring or aura. Photographs taken at a speed of of a second have proven that this is an illusion due to the persistence of vision, the actual fact being that there are formed hundreds of small individual streams 1 4 of molten slag which are projected along straight lines which are tangents of the periphery of the rotor.

It will be self-evident from consideration of the physics involved that each stream of the melted slag, as it leaves the'circular edge 13 of the rotor 3, will tend to travel in a straight line tangent to the circle that defines the said circular edge 13. The pictures have proven this. It has been definitely ascertained, so far as the discharge of the molten material from the edge 13 of the rotor 3 is concerned, that the speed is insufficient to fiberize the slag. What appears to happen is that the slag is thus subdivided. into an extremely large number of individual little streams 14 which are in an ideal condition to have. imparted to them the necessary momentum to attenuate them into fibers. For the purpose of doing this there is provided a blasting ring or nozzle 15 through which a suitable gas, for example, steam, may be passed from the supply line 16. This is arranged concentric with the rotor and has a slightly larger radius than the latter. The steam issues from a number of individual small openings 17 which can best be seen in Fig. 2 in which, however, only a much smaller number than those actually used is shown. I

The steam, which passes out of the annular nozzle 15, strikes the small streams 14 of the thus subdivided slag. By intercepting the outwardly traveling streams 14 with the annular steam blast, these streams are diverted into a new path, and by reason of the high velocity imparted thereto, soon become attenuated into individual fibers 19, which enter a suitable blow chamber (not shown) where they collect. Particles, such as slugs and beads 18 and. 19-will travel outwardly and thus become separated from the fibers.

As the annulus 12 remains in the inside. of the rotor 3 for some time, a small amount of it will. tend to adhere to the surface of the metal. In accordance'with the present invention such adhesion is minimized, and sometimes entirely overcome, by providing a suitable interfacial material which reduces or destroys the adhesion between the slag and the metal of the rotor. Thus a small amount of organic carbon-yielding or lubricating material, such as an oil, grease, or graphite, or a suspension of graphite in an oil or grease, may be applied to the stream 11 of molten material or to the inside wall of the rotor. in the latter case the lubricant may be placed along any portion of the inside wall of the rotor between the annulus and the closed bottom 20 of the rotor, or even against the back wall 20 itself.

This may be done manually, through a pipe or by means-of a ladle. For sake of convenience, however, it is preferred to employ a suitable tank or container 21 which is used as a supply of lubricant. From this container there extends a suitable small pipe or tube 22 which may be provided with any suitable control valve 23. There may also be a branch line 24, in case it is desired to direct the lubricant or parting compound onto the molten stream 11.

Whenever the operator desires to clean the inside of the rotor, he may open one: or both of these valves for a brief moment so'that a few cubic centimeters of the lubricant will be deposited upon either the molten stream and/or upon the inside wall of the rotor.

Due to the mechanical forces involved as the result of the rapid rotation of the rotor, the lubricant or other carbonforming parting compound will work its way to the interface between the inside wall of the rotor and the shell of slag. This will take place despite the high temperature of the slag, and will result in loosening the shell of slag so that, if sufficiently loosened, it will automatically be ejected from the rotor. If it still has a slight tendency to stick, it may be readily dislodged by means of a hoe or hook or even by being touched with an iron rod. In fact, anything which will interfere with the slags continued rotation or slows it down relative to the speed of the metallic wall of the rotor will shear it loose.

Ordinarily it is preferred to work with a minimum of lubricant, so that there will be only a discharge of the shell when desired, as too frequent removal occasions a certain lossin material; although the skulls or shells may be re-charged into the cupola in which the slag or the like is originally melted.

The present invention, has been found to provide a safe and efficacious method of cleaning the rotors, and,

main principle or the invention is the broad concept of.

interposing asuitable parting compound between the hot slag and the metallic surface which supports it. Hence the invention may be applied to other forms and shapes of rotors, and therefore the illustration given hereinabove is to be considered as exemplificative and not as limiting. I claim: Method of facilitating the removal of hot adherent slag from a rotating metallic surface which comprises interposing a parting compound periodically between the slag and said metallic surface.

References Cited in the file of this patent UNITED STATES PATENTS 142,573 Lydiatt Sept. 9, 1873 205,781 Atterbury July 9, 1878 1,915,201 Ragg June 20, 1933 2,150,945 Slayter Mar. 21, 1939 2,305,l72 Landgraf Dec. 15, 1942 2,318,821 Wallrath et a1. May 11, 1943 2,365,970 Pearce Dec. 26, 1944 2,399,383 Powell Apr. 30, 1946 2,411,660 Manning Nov. 26, 1946 2,460,977 Davis et al. Feb. 8,. 1949 2,587,710 .Downey Mar. 4, 1952 FOREIGN PATENTS 16,349 GreatBritain Nov. 28, 1887 103,175 Australia Feb. 17, 1938 

